Mass Effect 2's combat is significantly different to that of the original Mass Effect.
The game focuses far more on the shooter element, and has a greatly improved cover mechanic. Both biotic and tech abilities are effective for dealing damage in combat, and cooldowns are global, but depend on the ability used. For example, Throw may cause a 2 second cooldown (on all abilities), whereas Warp causes a 4 second cooldown (again, on all abilities).
In addition, biotic and tech abilities can combine to form deadly explosions. For example, using Singularity on an enemy and then Warp will detonate the Singularity.
Teammates can be ordered to use certain abilities as before; opening the ability screen slows down the game and allows Shepard to use abilities himself or order his teammates to use them. Each teammate has their own cooldown.
Weapon usage is the same as before - dependent upon your class - but all classes can use Heavy Weapons, which usually have low ammunition but deal enormous damage.
